Methods and the corresponding device are presented for the correction of lateral chromatic aberration within a digital camera or other imaging device, using calibration approaches that do not require previously acquired lens data to effect the correction. An in-camera auto-calibration procedure is performed on the attached lens, such as when a lens is exchanged, and extracts parameters required for chromatic aberration correction, respecting zoom and focus, from one or more captured images. Based on image data extracted as a plurality of channels of a chromatic decomposition of the image, the chromatic aberration information for the lens is extracted. From the chromatic aberration information, the correction factors for the lens are determined.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for correcting chromatic lens aberrations in an imaging system, comprising: using a first lens to acquire image data for a first image; extracting chromatic aberration information for the first lens from the acquired image data, wherein the chromatic aberration information indicates displacement of a chromatic component of the image data relative to at least one other chromatic component of the image data; and determining, for a point radially located from an optical center of the first image, a correction factor for the first lens for one or more second channels of a chromatic decomposition of the first image with respect to a first channel of the chromatic decomposition based on the displacement of the chromatic component of the image data at the point, wherein the extracting and determining are performed by an on-camera image processor.
2. The method of claim 1 , wherein the image data is raw image data.
3. The method of claim 2 , wherein the raw data image is in a Bayer image decomposition format.
4. The method of claim 1 , wherein said first channel is a green channel and said one or more second channels are a red channel and a blue channel.
5. The method of claim 1 , wherein said first lens is a zoom lens and said image data is acquired for a plurality of different focal length settings.
6. The method of claim 5 , wherein the number of different focal length settings is three.
7. The method of claim 5 , wherein said determining includes incorporating variations in said correction factor based on focal length setting.
8. The method of claim 1 , further comprising: using the first lens to acquire image data for one or more second images; and extracting additional chromatic aberration information for the first lens from the image data acquired for the second images, wherein said determining the correction factor for the first lens incorporates the additional chromatic information.
9. The method of claim 1 , further comprising: storing the correction factor as one or more look up tables.
10. The method of claim 1 , wherein the first image is a monochromatic text image.
11. The method of claim 1 , wherein the first image is a monochromatic test pattern.
12. The method of claim 11 , wherein said test pattern is supplied by a manufacturer of one or more elements of the imaging system.
13. The method of claim 12 , wherein said test pattern includes multiple symmetrical copies of a pattern.
14. The method of claim 1 , wherein the first image is generated by an attachment to a flash apparatus.
15. The method of claim 1 , further comprising: subsequently replacing the first lens with a second lens; acquiring image data using the second lens; and extracting chromatic aberration information from the acquired image data using the second lens and determining correction factors for the second lens therefrom.
16. The method of claim 1 , wherein said method is performed by a supplier of the imaging system.
17. The method of claim 1 , wherein said method is performed by a user of the imaging system.
18. The method of claim 1 , further comprising: using the first lens to acquire image data for a second image; extracting chromatic aberration information for the first lens from the image data acquired for the second image; and revising, from the chromatic aberration information extracted for the second image, the correction factor for the first lens, wherein the extracting of chromatic aberration information for the first lens from the image data acquired for the second image and the revising are performed by an on-camera image processor.
19. The method of claim 1 , further comprising: performing an on-camera image correction process of the first image using said correction factor.
20. The method of claim 1 , further comprising: using the first lens to acquire image data for a second image; performing an on-camera image correction process of the second image using said correction factor.
21. The method of claim 20 , wherein the first image is a preview version of the second image.
22. The method of claim 1 , wherein said image data is acquired for a plurality of different focus settings.
23. The method of claim 22 , wherein said determining includes incorporating variations in said correction factor based on focus setting.
24. An end user implementable method for correcting chromatic lens aberrations in an imaging system, comprising: attaching a first lens to the imaging system; subsequently initiating a process by the end user, the process including: using the first lens to acquire image data for a first image; extracting chromatic aberration information for the first lens from the acquired image data, wherein the chromatic aberration information indicates displacement of a chromatic component of the image data relative to at least one other chromatic component of the image data; and determining, for a point radially located from an optical center of the first image, a correction factor for the first lens for one or more second channels of a chromatic decomposition of the first image with respect to a first channel of the chromatic decomposition based on the displacement of the chromatic component of the image data at the point, wherein the extracting and determining are performed by an on-camera image processor.
25. The method of claim 24 , wherein the image data is raw image data.
26. The method of claim 25 , wherein the raw data image is in a Bayer image decomposition format.
27. The method of claim 24 , wherein said first channel is a green channel and said one or more second channels are a red channel and a blue channel.
28. The method of claim 24 , wherein said lens is a zoom lens and said image data is acquired for a plurality of different focal length settings.
29. The method of claim 28 , wherein the number of different focal length settings is three.
30. The method of claim 28 , wherein said determining includes incorporating variations in said correction factor based on focal length setting.
31. The method of claim 24 , further comprising: using the first lens to acquire image data for one or more second images; and extracting additional chromatic aberration information for the first lens from the image data acquired for the second images, wherein said determining the correction factor for the first lens incorporates the additional chromatic information.
32. The method of claim 24 , the process further comprising: storing the correction factor as one or more look up tables.
33. The method of claim 24 , wherein the first image is a monochromatic text image.
34. The method of claim 24 , wherein the first image is a monochromatic test pattern.
35. The method of claim 34 , wherein said test pattern is supplied by a manufacturer of one or more elements of the imaging system.
36. The method of claim 35 , wherein said test pattern includes multiple symmetrical copies of a pattern.
37. The method of claim 24 , wherein the first image is generated by an attachment to a flash apparatus.
38. The method of claim 24 , the process further including: using the first lens to acquire image data for a second image; extracting chromatic aberration information for the first lens from the image data acquired for the second image; and revising, from the chromatic aberration information extracted for the second image, the correction factor for the lens, wherein the extracting of chromatic aberration information for the first lens from the image data acquired for the second image and the revising are performed by an on-camera image processor.
39. The method of claim 24 , the process further including: performing an on-camera image correction process of the first image using said correction factor.
40. The method of claim 24 , further comprising: using the first lens to acquire image data for a second image; performing an on-camera image correction process of the second image using said correction factors.
41. The method of claim 40 , wherein the first image is a preview version of the second image.
42. The method of claim 24 , wherein said image data is acquired for a plurality of different focus settings.
43. The method of claim 42 , wherein said determining includes incorporating variations in said correction factor based on focus setting.
44. A method of operating an imaging system, comprising: causing the imaging system to project a test pattern; using a first lens to acquire image data for the test pattern; extracting chromatic aberration information for the first lens from the acquired image data, wherein the chromatic aberration information indicates displacement of a chromatic component of the image data relative to at least one other chromatic component of the image data; and determining, for a point radially located from an optical center of the first image, a correction factor for the first lens for one or more second channels of a chromatic decomposition of the image data with respect to a first channel of the chromatic decomposition based on the displacement of the chromatic component of the image data at the point, wherein the extracting and determining are performed by an on-camera image processor.
45. The method of claim 44 , wherein the test pattern is projected by a flash apparatus.
46. The method of claim 45 , wherein an attachment to the flash apparatus is used to produce the test pattern.
47. A digital imaging system, comprising: a first lens system; a sensor section on to which said first lens system forms an image, which in operation provides image data for a first image; and an on-camera image processor electrically coupled with the sensor section, which in operation receives said image data, extracts chromatic aberration information from said image data, wherein the chromatic aberration information indicates displacement of a chromatic component of the image data relative to at least one other chromatic component of the image data; and determines, for a point radially located from an optical center of the first image, a correction factor, based on the displacement of the chromatic component of the image data at the point, for the first lens for one or more second channels of a chromatic decomposition of the first image with respect to a first channel of the chromatic decomposition of the first image.
48. The system of claim 47 , wherein the on-camera extracting and determining are performed as an end user implementable process.
49. The system of claim 47 , wherein the sensor section provides the image data as raw image data.
50. The system of claim 49 , wherein the sensor section includes a Bayer grid filter and provides the image data in a Bayer image decomposition format.
51. The system of claim 47 , wherein said first channel is a green channel and said one or more second channels are a red channel and a blue channel.
52. The system of claim 47 , wherein said first lens system is a zoom lens and said correction factor are determined for a plurality of different focal length settings.
53. The system of claim 52 , wherein the number different focal length settings is three.
54. The system of claim 52 , wherein said correction factor incorporates variations based on focal length setting.
55. The system of claim 47 , further comprising: a memory, wherein the image processor stores one or more look up tables for the correction factor.
56. The system of claim 47 , wherein the first image is a monochromatic text image.
57. The system of claim 47 , wherein the first image is a monochromatic test pattern.
58. The system of claim 57 , wherein said test pattern is supplied by a manufacturer of one or more elements of the imaging system.
59. The system of claim 57 , wherein said test pattern includes multiple symmetrical copies of a pattern.
60. The system of claim 47 , further including: a flash apparatus, wherein the first image is generated by an attachment to a flash apparatus.
61. The system of claim 47 , further including: a second lens system, wherein the first and second lens systems are interchangeably mountable to provide an image to the sensor section, wherein the image processor can extract chromatic aberration information from an acquired image data using the second lens system and determine correction factors for the second lens system therefrom.
62. The system of claim 47 , wherein the image processor can revise the correction factor for the first lens system using image data acquired for a second image.
63. The system of claim 47 , wherein the image processor performs an on-camera image correction process of the first image using said correction factor.
64. The system of claim 47 , wherein the sensor section further provides image data for a second image, wherein the image processor performs an on-camera image correction process of the second image using said correction factor.
65. The system of claim 64 , wherein the first image is a preview version of the second image.
66. The system of claim 47 , wherein the image processor further determines the correction factor for the first lens system using image data acquired for one or more second images.
67. The system of claim 47 , wherein said correction factor is determined for a plurality of different focus settings.
68. The system of claim 67 , wherein said correction factors include variations based on focus settings.
69. A digital imaging system, comprising: one or more interchangeable lens systems; a mount onto which said one or more interchangeable lens systems can be attached; a sensor section on to which an attached lens system forms an image, which in operation provides image data for a first image; and an on-camera image processor electrically coupled with the sensor section, which in operation receives said image data, extracts chromatic aberration information from said image data, wherein the chromatic aberration information indicates displacement of a chromatic component of the image data relative to at least one other chromatic component of the image data, and determines from the chromatic aberration information, for a point radially located from an optical center of the first image, correction factors for the attached lens system for one or more second channels of a chromatic decomposition of the first image with respect to a first channel of the chromatic decomposition of the first image based on the displacement of the chromatic component of the image data at the point, wherein the extracting and determining are performed by the image processor in an on-camera end user implementable process upon attaching a first of the lens systems.
70. The system of claim 69 , where the sensor section provides the image data as raw image data.
71. The system of claim 70 , where the sensor section includes a Bayer grid filter and provides the image data in a Bayer image decomposition format.
72. The system of claim 69 , wherein said first channel is a green channel and said one or more second channels are a red channel and a blue channel.
73. The system of claim 69 , wherein said first lens system is a zoom lens and said correction factors are determined for a plurality of different focal length settings.
74. The system of claim 73 , wherein the number of different focal length settings is three.
75. The system of claim 73 , wherein said correction factors include variations based on focal length setting.
76. The system of claim 69 , further comprising: a memory, wherein the image processor stores one or more look up tables for the correction factors.
77. The system of claim 69 , wherein the first image is a monochromatic text image.
78. The system of claim 69 , wherein the first image is a monochromatic test pattern.
79. The system of claim 78 , wherein said test pattern is supplied by a manufacturer of one or more elements of the imaging system.
80. The system of claim 78 , wherein said test pattern includes multiple symmetrical copies of a pattern.
81. The system of claim 69 , further including: a flash apparatus, wherein the first image is generated by an attachment to a flash apparatus.
82. The system of claim 69 , wherein the image processor can revise the correction factors for the first lens system using image data acquired for a second image.
83. The system of claim 69 , wherein the image processor performs an on-camera image correction process of the first image using said correction factors.
84. The system of claim 69 , wherein the sensor section further provides image data for a second image, wherein the image processor performs an on-camera image correction process of the second image using said correction factors.
85. The system of claim 84 , wherein the first image is a preview version of the second image.
86. The system of claim 69 , wherein the image processor further determines the correction factors for the first lens system using image data acquired for one or more second images.
87. The system of claim 69 , wherein said correction factors are determined for a plurality of different focus settings.
88. The system of claim 87 , wherein said correction factors include variations based on focus settings.
89. A digital imaging system, comprising: a built-in flash apparatus, which in operation projects a test pattern on a surface; a first lens system; a sensor section on to which said first lens system forms an image, which in operation provides image data from the test pattern; and an on-camera image processor electrically coupled with the sensor section, which in operation receives said image data and determines from chromatic aberration information extracted from the image data, for a point radially located from an optical center of the image, correction factors for the first lens system for one or more second channels of a chromatic decomposition with respect to a first channel of the chromatic decomposition based on a displacement of a chromatic component of the image data at the point, wherein the chromatic aberration information indicates the displacement of the chromatic component of the image data relative to at least one other chromatic component of the image data.
90. The digital imaging system of claim 89 , wherein an attachment to the flash apparatus is used to produce the test pattern.
91. A method for correcting chromatic lens aberrations in an imaging system, comprising: projecting an image onto an image sensor through a lens, wherein, in operation the image sensor acquires image data from the projected image; receiving at an on-camera image processor, the acquired image data; extracting by the on-camera image processor, chromatic aberration information for the lens from the acquired image data, wherein the chromatic aberration information indicates spatial displacement of a first chromatic component of a chromatic decomposition of the image data relative to a second chromatic component of the chromatic decomposition of the image data; determining from the extracted chromatic aberration information by the on- camera image processor, for a point radially located from an optical center of the image, correction factors for the lens for the second chromatic component of the chromatic decomposition of the image with respect to the first chromatic component of the chromatic decomposition; and applying the correction factors for the lens by the on-camera image processor to a pixel of the first image based on a radial displacement of the pixel relative to the optical center of the image.
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May 25, 2007
January 3, 2012
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